Circuit breaker linkage having a toggle link of variable length



R. B. HEILMAN ETAL v CIRCUIT BREAKER LINKAGE HAVING A TOGGLE March 22,1966 LINK OF VARIABLE LENGTH 6 Sheets-Sheet l Filed DeC. 24, 1962INVENTOR RAYMOND BHELMAN BY H Row H March 22. 1966 R. B. HEILMAN ETAL3,242,286

CIRCUIT BREAKER LINKAGE HAVING A TOGGLE LINK OF VARIABLE LENGTH FiledDeo. 24, 1962 6 Sheets-Sheet 2 It I INVENTOR.

RAYMOND B Hamm BY HARoLo H R.

March 22, 1966 R. B. HEILMAN ETAL 3,242,286

CIRCUIT BREAKER LINKAGE HAVING A TOGGLE LINK OF VARIABLE LENGTH 6Sheets-Sheet 5 Filed Dec. 24, 1962 \Ol 8\ 8O 57 82 348mg H34 Ob 8 9@ 5835 40 548 65 5@ '7o lo@ 57 SUSDENsmN STRCTUQE 4o BQOKEM 'www 54 Hana mxoPmrLvom-rfeo Pore Lr-amm ,Mm u

HIHIH m UGS March 22, 1966 R. B. HEILMAN Erm. 3,242,285

CIRCUIT BREAKER LINKAGE HAVING A TOGGLE LINK 0F VARIABLE LENGTH FiledDec. 24, 1962 6 Sheets-Sheet 4 H5 57 n4 48 9 H5 INVENTOR. RAYMONDB.HE|LMAN BY HAROLD AHR March 22, 12966 R. B. HEILMAN ETAL 3,242,286CIRCUIT BREAKER LINKAGE HAVING A TOGGLE LINK OF VARIABLE LENGTH 6Sheets-Sheet 5 Filed Dec. 24, 1962 INVENTOR.

March 22, 1966 R. B HEILMAN Erm.

. CIRCUIT BREAKER LINKAGE HAVING A TOGGLE LINK OF VARIABLE LENGTH 6Sheets-Sheet 6 Filed DSG. 24, 1962 F O l @E 515m I lo F C.. AD O 4 /N/ mOPENlNGS SPRWGS N S m V @umm MEA o WH W WB n OHM@ w I Mmm Y AA RH wUnited States Patent v 3,242,286 CIRCUIT BREAKER LIN KAGE HAVING ATOGGLE LINK F VARIABLE LENGTH Raymond B. Heilman, Trenton, NJ., andHarold H.

Bahr, Bronx, N.Y., `assignors to Heinemann lElectric Company, Trenton,NJ., a corporation of New Jersey Filed Dec. 24, 1962, Ser. No. 246,699Claims. (Cl. 200-106) This invention relates to electric circuitbreakers and,

more particularly, to an improved vibration and shock resistantmechanical linkage arrangement for connecting the operating handle tothe movable contact arm in a circuit breaker intended to operate betweenextreme ambien-t temperature limits.

It is an object of -this inevntion to provide a linkage move to the openposition when a overload of a predetermined magnitude `persists inthecircuit.

A still further object is to provide a movable contact arm connected toa linkage, the movable contact arm being provided with an improved,simplified arrangement to roll and slide the movable contact (duringopening movement of the arm) and abruptly move it so as to break anybond that may have formed between the contacts for facilitating theopening of the contacts.

In one embodiment of this invention a circuit breaker is provided with apair of separable contacts, one of the contacts being mounted upon amovable contact arm, the latter being pivotal from a contacts closedposition to a contacts open position and suitably biased by a spring tothe open contacts position. A iirst or handle toggle group of links isprovided including a vhandle link connected lto a second link of varyinglength and together `jointly forming a toggle. A second or main togglegroup of links is also provided, the main toggle group of links 4beingconnected by an insulator coupler link to the handle toggle 4group oflinks. The main toggle group of links comprises toggle links one ofwhich is connected 'to a catch link and the other to the movable contactarm. The coupler link is connected to the knee of the main toggle andthe catch link is controlled by ya rockable cradle and anelectromagnetic means. l

Suitable stop means are provided for the handle toggle corresponding tothe contacts closed and contacts open positions. The main toggle isprovided with means for 'limiting its overcenter travel in the contactsclosed position and, further, the movable arm is provided with a stoppin for limiting its movement in the contacts open position.

In the contacts open position, the handle toggle is locked in anovercenter position by a spring carried by the link of varying lengthwhich also locks the handle 'toggle in an overcenter position when inthe contacts closed position, but on the`other side of the toggle centerline. Also, 'in the closed position of the contacts the main togglelinks are locked in the overcenter position by the bias of the movablecontact opening spring. The coupler link transmits the manual force atthe handle (during manual opening and closing) 'to the main toggle, aswell a's vtransmitting an initial resetting force from the main toggleto the handle toggle, but when the handle and main toggles are at restin the closed position of the contacts they are stable independently ofeach other and of the coupler link which connects them. Therefore, :it

3,242,286 Patented Mar'. 22, 1966 ICC independent, overcenter lockedtoggles are provided by the links of the mechanism to better resistvibration and shock forces tending to open the contacts of the circuitbreaker.

The foregoing and other objects of the invention, the principles of theinvention, and the best mode in which it is contemplated applying suchprinciples will more fully appear from the following description andaccompanying drawings in illustration thereof.

In the drawings,

FIG. l is a view, partly in section and partly in elevation, of acircuit breaker incorporating this invention with the linkageillustrated in the contacts open position;

FIG. 2 is a view similar to FIG. 1 of the same circuit breaker butillustrating the contacts closed position and taken along the line 2 2in FIG. 8;

FIG. 3 is a view similar to FIG. 2 but illustrating the position of thelinkage when the circuit breaker is tripped electromagnetically and aforce is applied to the handle preventing the handle from automaticallymoving to the contacts open position, that is, the trip free position;

FIG. 4 is a sectional view taken along the line 4 4 in FIG. 3 but partof the suspension structure for the movable tube has been broken awayfor illustrative purposes;

A FIG. 5 is a partial view ltaken along the line 5 5 in FIG. 4 but inFIG. 5 some of the suspension structure is illustrated which is notillustrated in FIG. 4;

FIG. 6 is a partial, perspective view illustrating part of the linkagein the contacts closed position;

FIG. 7 is a view, partly insection and partly in elevation, for theposition of the mechanism illustrated in FIG. 2 with the outer casebroken away to better show the relation of the mechanism to the frameplates supporting it;

FIGS. 8, 9, and 10 are sectional views taken along the lines 8 8, 9 9and 10 10 in FIG. V7;

FIG. 1l is a top view taken along the line 1v1 11 in FIG. l lbut showingthe movable tube in elevation; and

FIG. l2 is a diagrammatic view of the linkage after electromagnetictripping and upon initial movement of the handle toward the contactsopen position but prior to com-plete automatic resetting of themechanism when no force is applied to the handle tending to hold it inthe contacts closed position.

Referring to the drawings, there is illustrated a circuit breaker 10including an outer case 11 and terminal structures 12 and 13 extendingtherefrom. The terminal structure 12 is connected within the case by aconductor 14 to a coil 15 forming part of an electromagnet 16. Theelectromagnet 16, on predetermined overload current conditions, movesaxially a tube 2t), which is .partly formed of magnetic material, andfunctions as an armature for the coil 15. The tube 20 controls a linkagemechanism 21 of the circuit breaker for automatically (on predeterminedoverload conditions) opening the contacts 22 and 23 by moving thecontact 22 out of engage- -ment with the stationary contact v23, themovable contact 22 being carried by a movable contact arm 24 pivoted atthe right on laterally projectingkfeet 25. A movable armature (notillustrated) of magnetic material is enclosed by the tube 20 andcontrols movement downwardly of the tube 20 at certain currentconditions by 'itself first -so moving toward the coil 15 to thereafterinitiate (after a time delay period) movement of the tube 20, but athigher overload currents movement downwardly of the tube 20 takes placewithout the need for prior movement of the enclosed movable armature(i.e. instantaneously). Claims to various features relating to the tube20 are presented in a separate application led January 18, 1963 byRaymond B. Heilman, Serial No. 252,404 and, hence, the tube 20 is notdescribed in detail herein.

The coil 15 is formed by a suitable number of turns of wire electricallyinsulated from each other and wound upon a metal tube of nonmagneticmaterial. A magnetic frame 27 for the coil 15 is provided by an openended almost completely annular tube, except for the slot 28 (FIG. 2)through which extends a flexible conductor 29 connected to the movablearm 24. The frame 27 covers and closes the top and extends to the bottomof the coil 15. The bottom of the magnetic frame tube 27 is closed by amagnetic pole piece 31 extending within and just short of the middle ofthe length of the coil and having a slot (not shown) extending axiallysimilarly to slot 28. VSecured to the pole piece 31 is a bearing 32through which extends a projection 33 of the tube 20.

Manual opening and closing of the contacts 22 and 23 is initiated yby ahandle 34 and a handle link 35, whereas electromagnetic tripping of thecontacts to the open position is initiated by pivotal movement of a lock36 (FIGS. and 7) upon being actuated by a pivotal arm 37 ofcounterweight suspension structure 40 after suitable axial movement ofthe tube 20 toward the coil 15.

The mechanism 21 comprises two groups of links referred to forconvenience as the handle toggle or first group 41 and the main toggleor second group 42, the two groups being interconnected by an insulatorcoupler link 43 to transmit forces between the groups during manual andautomatic operation. The handle toggle group 41 comprises, in additionto the handle link 35, a link 44 of varying length, hereinafterdescribed in detail.

The main toggle group of links 42, comprises upper Vand lower togglelinks 48 and 49 (formed by spaced members, FIGS. 4 and 8), controlled bya catch link 50 which is pivotal about fixed pintle 51, the lower togglelink 49 being pivotally connected at its lower end to the movable arm 24by a pintle 52. As illustrated in FIG. 2, the upper toggle link 48 hasits upper end pivotally connected by a pintle 53 to one end of the catchlink 50 while the adjacent ends of the toggle links 48 and 49 arepivotally connected together by another pintle 54 to form the knee ofthe main toggle. Overcenter travel of the knee 54 in the closed positionof the contacts, FIG. 2, is limited by abutment of the upper extension56 of link 49 with the iixed lpintle 51.. In the main toggle group 42,the pintle 51 for the catch link 50 is the only link which is pivotedabout a iixed pintle, the other pintles being capable of floatingmovement, the pintle 51 being supported at its end portions in spacedframe plates 57 and 58.

The catch link 50 is controlled by a cradle 61, the upper end of sideplate 62 (one of the two side plates forming cradle 61) being in turnrestrained (FIG. 10) by the inturned pivotal latch 63 of lock 36. Thecradle 61 is biased in a clockwise direction (as viewed in FIG. 2) by aspring 64 (FIGS. 3, 5 and 10) which is coiled about and carried by a pin65, the spring 64 having one end (the left hand end in FIG. 3) anchoredagainst the frame plate 58 while the other end (the right hand end)underlies and is biased against a pin 66 which is carried by plates 57and 58 and about which the cradle 61 pivots. Also, clockwise movement ofthe cradle 61 is limited due to abutment of the edges of the cradle sideplates with the coil frame 27, FIG. 1.

The latch 63 is pivoted clockwise, FIG. 5, to release the cradle 61, byimpingement of the arm 37 (of the counterweight suspension structure 40secured to the tube 2t) and moved downwardly upon predetermined overloadcurrents) with a trigger arm 70 of the lock 36. Rotation of the latch 63allows the cradle 61, under pressure from two opening springs '71connected to the movable arm 24, to rotate counterclockwise until thecatch link 50 frees itself from a lock 72 carried by the cradle 61.

Returning to the handle toggle group 41, the variable length link 44 inFIG. 1 comprises a ygenerally inverted L-shaped link 75 pivotal about afixed pintle 76 whose ends are carried by insulator bearing 77 supportedby the frame plates 57 and 58, the ends of the pintle 76 extendingthrough an inner case 145 and into contact with the main case part 144l(as illustrated in FIG. 8). The other end of the L-shaped link 75 ispivotally connected to a floating link 80 and the latter is in turnpivotally connected to the lower end of the handle link 35, theconnections being made by a U-shaped member whose legs form pintles 81and 82, respectively, as illustrated in FIG. 4. Wrapped around the bodyportion of the L-shaped link '75 is a spring 83 which is compressed by aslidable link 84, the latter having shoulder portions 87 (FIG. 8)resting u-pon the upper end of the spring 83, the lower end of thespring 83 resting against the pintle 76. The slidable link 84 also has alower portion 88 in interfitting, cruciform relationship with thelongest part of the L-shaped link 75 (for alignment purposes) andintermediate the pintles 76 and 82. The upper portion of slidable link84 is split to form V-shapes (FIG. 6) and is seated and biased againstthe pintle 81 by the spring 83 in all positions of the mechanism.

The position of the pintle 82 changes in different positions of thelinkage but the pintle 82 is placed relative to the other pintles andthe links so that when the handle link 35 is held manually in itscontacts closed position (illustrated in FIG. 3), the toggle links 48and 49 are 'allowed to collapse to fully open the contacts by rotationof the coupler link 43 about pintle 82, which due to the manual force onthe handle 34, remains stationary.

Movement of the handle link 35, about its tixed pintle 91, is limited byabutment (in the off position of the contacts) of the handle link 35with the stop pin 92, and (in the contacts closed position) by the stoppin 93. It will be noted that the relative position of the various linksand the placement of the pintles of the handle toggle group 41 is suchthat the pintle 81 defines the knee of a toggle formed by the handlelink 35 and the variable length link 44 (i.e. links 75, 80, 84 andspring 83). Thus, when the pintle 81 is to one side or the other of acenter line extending between the pintles 76 and 91, the spring 83exerts a force on the pintle 81 tending to move the handle link 35 witha snap action until it abuts with the stops 92 or 93.

The characteristic of this mechanism of -high stability to shock andvibration forces is seen by reference to FIG. 2 because the handle groupof links 41 is locked in its contacts closed position independent of themain toggle group of links 42 which is also locked in the contactsclosed position, i.e., the coupler link 43 could be removed at such timewithout disturbing the stability of the linkage.

From the foregoing it is seen that in manual movement of the linkage itis possible to View the handle toggle group of links 41 and four of thelive links of the main toggle group of links 42 as forming a four-bargroup, but when the mechanism is tripped electromagnetically the tivelinks of the main toggle group of links 42 becomes a five-bar group.That is, the four bars of the handle toggle group 41 are links 35, 75and 80 with an imaginary link extending from pintle 76 to pintle 91.During manual opening or closing of the contacts, the four bars of themain toggle group 42 are links 24, 48, 49 (catch link 50 being iixed atthis time) with an imaginary link extending from pin 53 to the feet 25of the movable arm 24. Upon electromagnetic tripping and release of thecatch link 50, the aforedescribed four-bar group of the main togglegroup of links becomes a fivebar group because the catch link 50 nowbecomes the fourth link of the live-bar mechanism, and an imaginary linknow extending from pin 51 to the feet 25 of the movable arm.

The lock 36 is statically balanced and pivotally mounted upon a pintle96 which is staked to frame plate 58 and provided with an enlarged headto hold the lock 36 in proper position. The latch 63 is biased intolocking engagement with the cradle 61 by a spring 97 having one endsecured to the frame plate 58 and the other end to an arm 98 of the lock36.

The counterweight suspension structure 40 (FIG. 5) is formed by spacdplates 101 and 102 (FIG. 4) which are pivoted intermediate their ends onpintles 103 secured to bendable arms 104, the latter being welded attheir right hand ends to the frame plates 57 and 58. The spaced plates101 and 102 are also pivotally connected by pintles 106 to the tube 20,the pintles 106 being secured to the right of pintles 103 and to thetube 20 by a strap 107 which frictionally and tightly engages the outersurface of the tube 20' and is carried thereby. Springs 108 are providedto bias the pintles 106 above or below the pintles 103, the springs 108having their right hand ends connected to the counterweight plates 101and 102 between pintles 104 and 106. The counterweight structure 40 isclaimed in a separate patent application led January 18, 1963 by RonaldNicol, Serial No. 252,413 and therefore is not described in greaterdetail herein.

The movable arm 24 is at all times biased to the open position of thecontacts by the two springs 71, the lower ends of which are connected toopposite sides of the movable arm 24 at the pin 52 which also extendsbeyond the width of the movable arm 24 (FIG. 8) at both ends to engagethe frame plates 57 and 58 and thereby limit the travel of the movablearm 24 during the opening of the contacts (FIG. 3). The upper ends ofsprings 71 are secured to ears 113 carried by a pivotal plate 114, thelatter being pivotally supported in bearing notches 115 (FIG. 6) formedin the fra-me plates 57 and 58.

Upon release of the catch link 50, when there is no manual force onhandle 34 tending to hold the contacts closed, a sufficient force fromthe opening springs 71 and a contact force spring 117 (at such time) istransmitted by lower toggle link 49 to the coupler link 43 and thefloating link 80 for moving the knee pintle 81 of the handle togglegroup 41 to the left (beyond a center link extending between xed4pintles 76 and 91) at which time the force of spring 83 completes theresetting of the mechanism, such overcenter movement of the pin 81taking place (at such time) before a reset spring 119 is engaged by thecatch link 50. The force of spring 83 rotates the catch link 50counterclockwise into latching engagement with lock 72. Of course, atall times the cradle 61 and the lock 36 are biased clockwise andcounterclockwise respectively, by their springs.

When the contacts are closed, the component of the springs 71trans-mitted by the toggle links 48 and 49 also biases the catch link 50clockwise against the lock 72. After the contacts open, however, duringautomatic resetting, this component of springs 71 decreases in magnitudeand exerts a force on the catch link 50 which is less than that ofspring 83, whereby the catch link 50 resets due to the force of spring83. The lock lip 72 is carried in triangular slots 85 and biasedupwardly against one edge wall of the slots 85, by the end portions of aU-spring 86, FIG. 5, the latter having coil portions looped about thepin 65 carried by the cradle 61 and the middle or yoke portion biasedagainst the pintle 66 providing the pivotal support for the cradle 61and the ends of the pintle 66 being supported by the frame plates 57 and58, the latter being provided with openings 90 to accommodate therocking movement of the ends of the pin 65 when the cradle 61 moves.

For automatic resetting of the mechanism after removal of a force on thehandle 34 tending to keep the contacts closed while an overload persistsin the circuit requiring the contacts to open, the pivotal plate 114carries the leaf reset spring 119 (FIGS. l and 6) disposed in the pathof movement of the upper end of the catch link 50 (when Imovement of thehandle 34 to the contacts open position is restrained) subsequent to there- 6 lease of the catch link 50 by the lock 72, for depressing thereset spring 119, using the force obtained from the opening springs 71after electromagnetic tripping.

Welded to the outer cylindrical magnetic frame 27, positioned so as tobe between the side plates of the cradle 61, is a booster spring 121also for use during automatic resetting after trip free operation. Thebooster spring 121 (FIGS. l and ll) comprises a flexible leaf 122extending above the coil frame 27 and in the path of movement of andllexed by the pivotal plate 114 which carries the reset spring 119 andthe opening springs 71. Force from the opening springs 71 is stored bythe reset spring 119 and the booster spring 121 during movement of thelinkage from the position of FIG. 2 toward that of FIG. 3, until theforce restraining movement of the handle 34 to the contacts openposition is removed or reduced siliciently, at which time, since thecoupler link 43 and the upper toggle 48 are in force Atransmittingrelation by being in approximately end-to-end relation, the force storedby the reset spring 119 (transmitted through the floating link moves theknee pintle 81 of the handle toggle group 41 from the positionillustrated in FIG. 2 to the other side of a center line extendingbetween the pintles 76 and 91, whereupon 4the force of spring 83 alsohelps complete movement of all the links of the handle toggle group 41and the main toggle group 42 to the contacts open position.

Pivotal movement of the arm 24, and rolling and sliding movement betweenthe movable contact 22 and the stationary contact 23, is provided byelongated, open-ended slots 125 (FIG. 6), formed in each of the frameplates 57 and 58, which receive the laterally extending feet 25, lthelatter provided at the right ends of the side plates forming the movablearm 24. Coiled about an insulator bearing 126 carried by the frameplates 57 and 58 through which extends a pin 127 (FIGS. 1 and 6) is theContact force spring 117 having its ends biased against the feet 25 anda yoke portion 129 resting against a pin 130, the pin 130 being peenedto the frame plates 57 and 58. Each of the slots 125 is defined by a toparcuate wall 131 and two side walls 132 and 133, the latter two beinginclined toward each other to form a V shape, the wall 132 beingcontinued downwardly and vertically as wall 134 to form the lowerportion of each slot 125, while the wall 133, however, is continueddownwardly as wall 133, but inclined in the opposite direction to thewall 133, to jointly form substantially a point and together with wall136 the lower open ended portion of each slot 125.

In movement ofthe linkage from the off position (FIG. l) to the onposition (FIG. 2 or FIG. 6) the feet 25 pivot about the point juncturesof the walls 133 and 136 while Ithe upper edges slide along the arcuatewalls 131 until the movable contact 22 abuts the stationary contact 23,the linkage being proportioned so that the contacts abut before thetoggle links 48 and 49 go overcenter to the right, at which timecontinued movement of the handle 34 moves the feet 25 downwardly and tothe right along walls 136, about the stationary contact 23 as a fulcrum,the upper edges of feet 25 becoming spaced from the arcuate walls 131 atthis time, simultaneously depressing the ends of spring 117.

When the contacts open, initial movement of the movable arm 24 is asliding movement of the movable contact 22 along the stationary contact23, because the feet 2S slide to the left (along the walls 136) andupwardly, under the bias of the spring 117, until the upper edges offeet 25 jar or abut with an impact upon the arcuate walls 131.Thereafter, the opening springs 71 continue the opening movement of thearm 24, pivoting the arm 24 at its feet 25 about the point formed bywalls 133 and 136.

Coiled about the pin 130 is a reset spring 138 for the -tube 20. Thespring 138 has one end secured to a plate 139 which is in turn securedto the projection 33 of the tube 20. The other end of the spring 138 isdisposed to the left of an extension 140 secured to one of the feet 25.The extension 140 and the associated end of spring 138 are arrangedrelative to each other so that in the closed position of the contacts,FIG. 2, the extension 140 is spaced from the spring 138 and the springapplies no bias to the tube 2f), at this time. However, when themechanism moves from the contacts closed to the contacts open position,whether by manual movement of the handle 34 or electromagnetically byrelease of the cradle 61 by the lock 36, the extension 140 engages theassociated end of the spring 138 and depresses it, causing the other endof the spring 138 to exert a force upwardly upon the tube which issuflicient, upon deenergization of the coil 15 (thatis, extinction ofany arc that may form) to reset the tube 20 by moving it upwardlysufficiently for the pin i106 of the counterweight structure 40 to moveabove the center of pin 103, at which time the sus-pension spring 108also helps to move the tube 20 up to its reset or open position of thecontacts.

, The case 11 comprises a main case part 144 to which is brazed the rim158 of a bottom terminal block 146. A partial inner case 145 isprovided, welded to the bottom terminal block 146 for the purpose ofholding the pintles 76 and 127 (and their insulator bearings) in properalignment during assembly of the unit, the pintles 76 and 127 extendingthrough the inner case 145 and are peened thereto. The plates 57 and 58are also held in spaced relation with the side walls of the main casepart 144 because the ends of pintles 51 and 130 are peened to hold theplates 57 and 58 against shoulders 147 formed by the insulator 'bearing77 (FIGS. 4 and 8) and similar shoulders formed by the insulator bearing126. The mechanism is located properly with respect to the case by aninsulator 151 (carried by a handle bracket 152 brazed to the case part144) which receives groove portions 153 of the frame plates 57 and 58.The fixed pintle 91 for the handle link is supported by the bracket 152,the top part of the latter projecting out of the main case part 144 sothat the holes for pin 91 are above the top of the case part 144, and ametal bellows 154 is provided to seal the opening 155 in the main casepart 144 through which the handle link 35 extends, while at the sametime allowing pivotal movement of the handle link.

The assembly of the device heretofore described is made by firstassembling the aforementioned links and pintles to the frame plates 57and 58, the magnetic frame 27 of the coil 15 being secured by brackets156 to the frame plates 57 and 58 (FIG. 7), and the tube 20 beingcarried in proper position by the counterweight suspension structure 40.The linkage, assembled to the frame plates 57 and 58, together with thecoil 15, tube 20, and the terminal block 146 are now inserted into themain case 144 until the handle link 35 extends through the hole 155 inthe main case 144 and between the side plates of the handle brack- `et152 and until the locating insulator 151 is received in the grooves 153in the frame plates 57 and 58.

The pin 91 is then inserted to secure the handle link 35 to the -handlebracket 152 `and the opposite walls of the main case 144 are spot weldedto the opposite ends of the pintles 76 and 127. Thereafter, the maincase 144 is brazed to the rim of the terminal block 146. The handle 34is crimped to the link 35 and includes a lower inverted dished flange160 to which is brazed the upper end of the metal bellows 154. The lowerend of the bellows 154 is brazed to a dish shaped iiange 161 which issealed to the main case part 144.

Thus, it is seen that due to the locating insulator 151, the insulatorbearings 77 and 126, and the insulator coupler link 43, the outer met-alcase p-arts 144 and 146 are electrically insulated from the electricallyconducting parts of the circuit breaker since the terminals 12 and 13are electrically insulated from the metal supporting structure stormingpart of the terminal block by being embedded in a ceramic. Claims tovarious features relating to the terminals 12 and 13 are presented in aseparate application filed January 18, 1963 by Raymond B. Heilman SerialNo. 252,485 and, hence, they are not described in detail herein.

With the mechanism in the contacts open position, as illustrated in FIG.l, manual closing of the contacts is accomplished by manually moving thehandle 34 counterclockwise about the pintle 91. This movement of thehandle forces the knee pintle 81 to ymove the sliding link 84 downagainst the upward bias of the spring 83 and further compress thelatter, moving the pintle 81 from the position il-lustrated in FIG. 1,on the left of a center line connecting the pintles 76 and 91, towardthe right thereof. The L-shaped link carries the pintle 82 about thepintle 76 in a `manner to maintain links 43 and 80 in force transmittingrelation .and the L-shaped link 75 performs this same function duringelectromagnetic tripping. Continued counterclockwise movement of thehandle causes the pintle 81 to move through the center line betweenpintles 76 and 91, to the right hand side thereof, and the line ofaction of the spring 83 now moves from the left to the right of thisline also, the spring 83 now moving the `handle toggle link gro-up tothe right, with a snap action, until the handle link 35 abuts againstits stop pin 93, FIG. 2, the spring 83 remaining more compressed whenthe handle link 35 abuts the stop pin 93 than when it abuts stop pin 92.

When the linkage is turned to the closed position of the contacts, FIG.2, the toggle links 48 and 49 go overcenter to the right and the springforce of the opening springs 71 tend to rotate the catch link 50clockwise, but rotation of the catch link is restrained by the lock lip72.

Upon predetermined current conditions the tube 20 moves downsufficiently t0` pivot lock 36 and its latch 63 out of engagement withthe cradle side plate 62 at which time the catch link 50 is released bythe lock 72. The toggle formed by links 48 and 49 now collapsed to theleft and the movable arm 24 moves to its contacts open position underthe bias of the opening spring 71 and the contact force spring 117, asillustrated in FIG. ll.

It will thus be seen that when the circuit breaker heretofore describedis `associated with other similarly constructed circuit breakers formultipole operation and the handles are mechanically tied together by atie bar, for instance, the force of the opening springs 71 in theoverloaded pole (assuming only one of the multipoles is overloadedsufficiently to require the contacts to open) has to be sufiicient tostart not only the handle toggle knee moving past its center lineposition toward the left but also has to be sufficient to move thehandle links of the associated poles sufiiciently to make their handlelinks group go overcenter also. Of course, after the latter takes place,the spring 83 in the overloaded pole and the associated similar springsin the nonoverloaded poles all help to complete the movement of themechanisms to the contacts open positions.

Having described this invention, we claim:

1. In a circuit breaker, a pair of separable contacts, a movable contactann movable from a contacts closed to a contacts open position, anopening spring for biasing said movable arm to the open contactsposition, a rst group of links, a second group of links, a coupler linkconnecting said two groups of links for transmitting a force from one ofsaid .groups to the other of said groups, said first group of linkscomprising a handle link pivotally connected intermediate its ends to afixed pintle, a second link of variable length pivotally connected atone end to a fixed pintle and at the other end to a movable pintle forpivotally connecting the variable length link to one end of said handlelink, fixed stop pins for limiting pivotal movement of said handle linkt0 positions corresponding to the contacts closed and open positions, aspring carried by said variable length link, vsaid spring beingconnected intermediate the fixed pintle and the movable pintle -forlbiasing said handle link against one or the other of said stop pinswhen the movable pintleV said fixed pintles, and said second group oflinks comprising a rst toggle link and a second toggle link jointlyforming `a toggle having a pivotal knee to which one end of said couplerlink is connected, said first toggle link being pivotally connect-ed tosaid movable contact arm, manual movement of said handle link .beingtransmitted by said coupler link to said toggle for manually opening orclosing the contacts by movement of said toggle knee toward or away fromsaid first group of links, whereby the opening spring acting on themovable arm causes the movable arm to mo-ve to the open contactsposition, a catch link pivotal about another fixed pintle and pivotallyconnected at one end t said second toggle link, an electromagnetincluding .an armature for controlling said catch link, whereuponpredetermined current conditions and suicient movement of the armature,the Catch link is released, said catch link being 'biased by the openingspring so that upon release of the catch link it pivots and moves oneend of the second toggle link to the side of said knee which allows thetoggle to collapse under the bias of the opening spring, and a resetspring positioned in the path of movement of one of the links of saidsecond group of links to store energy therein received from the openingspring through the toggle links when movement of said handle link to thecontacts open position is restrained during said predetermined currentconditions, said reset spring moving said groups of links and thecoupler link to the off position after the movable arm Amoves toward itscontacts open position and after the restraint is removed from thehandle link.

2. In a circuit breaker, a pair of separable contacts, a movable contactarm movable from a contacts closed to a contacts open position, anopening spring for biasing said movable arm to the open contactsposition, a first group of links, a second group of links connected tosaid movable arm, a coupler link connecting said two groups of links fortransmitting a force from one group to the other, said first group oflinks comprising a handle link and a second link Ipivotally connected tosaid handle link and forming therewith a rst toggle having a pivotalknee, two stops for limiting overcenter travel of said first toggle tolocked positions corresponding to the contacts closed and contacts openpositions, a spring connected to the lirst toggle to bias said firsttoggle against one or the other of its stops when the knee of the firsttoggle is overcenter, said second group of links including a secondtoggle having a pivotal knee, said second toggle being formed by a thirdlink one end of which is connected to the movable arm, a fourth linkpivotally connected to the other end of the third link to form the kneeof the second toggle, a further stop for limiting overcenter lockingtravel of said second toggle when said movable arm is in the contactsclosed position, said fourth link being connected to a fifth link, saidfifth link being controlled by an electromagnetic means to move thefourth link relative to the knee o f the second toggle for permittingsaid second toggle to collapse under pressure of the opening spring uponpredetermined current conditions, .said opening spring biasing saidsecond toggle against said .further stop when said second toggle isovercenter, whereby the toggles of said first and second groups areindependently locked overcenter when said movable arm is in the contactsclosed position to minimize accidental movement of the movable contactarm to the contacts open position due to vibration and shock forces uponthe circuit breaker.

3. The structure recited in claim 2 wherein said coupler link is formedfrom insulating material, whereby the first group of links including thehandle link is electrically insulated from the electrically energizableportions of the circuit breaker.

4. The structure recited in claim 2 and further including a reset springin the path of movement of the fourth link, said fourth link and couplerlink together forming a l@ force transmitting arrangement, whereby theforce of said reset spring moves the knee of the first toggle towardsthe contacts open position when the movable arm moves to the contactsopen position, whereupon the bias of said first mentioned springcompletes the movement of all said links to the contacts open position.

5. In an electromagnetic circuit breaker, a pair of separable contacts,a movable conta-ct arm movable from a contacts closed to a contacts openposition, an opening spring for biasing said movable arm to the opencontacts position, a first group of links forming a first toggle, asecond group of links including a second toggle, a coupler linkconnecting said toggles, the link of said first toggle to which saidcoupler link is connected being of varying length, an electromagneticmeans for sensing a predetermined overload, said second group of linkscomprising a catch link controlled by said electromagnetic means formoving one end of said second toggle upon predetermined overloadconditions to collapse said second toggle for moving the movable contactarm to the contacts open position, a spring for biasing said firsttoggle to locked overcenter positions corresponding to the contactsclosed and contacts open positions, said second toggle being biased tothe locked overcenter position by said opening spring in the contactsclosed position independently of the first toggle, whereby the first andsecond groups of links are independently locked during the closedposition of the contacts.

6. The structure recited in claim 5 and further including a reset springmeans disposed in the path of movement of said catch link subsequent tooverload conditions and impingeable by said catch link when said firstgroup of links are restrained from moving during said predeterminedoverload thereby compressing said reset spring, said coupler link andone of the links of said second toggle being in force transmittingrelationship after collapse of said second toggle for moving said firsttoggle toward the open position of the contacts and moving the catchlink to its reset position during opening movement of the links of thesecond group of links, and a booster spring flexed by said reset springmeans to supplement the force of said reset spring means in resettingthe links, whereupon on removal of the restraint on said first group oflinks all of the links are automatically reset.

7. The .structure recited in claim 5 wherein said first and secondtoggles each include a pivotal knee, said coupler link is :pivotallyconnected at one end to the varying length link intermediate the endsthereof and at the other end pivotally connected to the knee of thesecond toggle, whereby upon collapse of the second toggle under pressureof the opening spring in the direction toward said first group of links,said coupler link rotates about its connection to the varying lengthlink until it transmits to the knee of the first toggle a component ofthe opening spring force at which time it moves the knee of the firsttoggle overcenter toward its contacts open position and thereafter thespring biasing the first toggle helps complete the movement of the linksto the contacts open position.

8. In an electric circuit breaker the combination of stationary andmovable contacts, a movable arm carrying said movable contact and havinga foot portion eX- tending transverse to the length of the arm, a frameplate having wall structure cooperating with said foot, said wallstructure including an arcuate upper wall and a rear wall formed bydiverging surfaces defining substantially a pivot point, an openingspring for biasing said arm to the contacts open position and againstsaid rear wall at all times, a contact force spring biasing said foottoward the arcuate upper wall, a linkage mechanism for manually closingand opening said contacts including a toggle connected to said movablearm, electromagnetic means for opening said contacts on predeterminedoverload currents, manual movement of said linkage meshanism in thedirection to close said contacts causing said foot to pivot about said-point and said contacts-to be engaged by each other before said toggleis fully extended, whereby continued movement in the contacts closingdirection of said linkage mechanism causes said movable arm to pivotabout the stationary contact as a pivot and the movable contact to rolland slide on the .stationary contact and the foot to slide along the`rear wall below said point, said toggle collapsing upon predeterminedoverload currents, whereby said contact force spring moves said footagainst said arcuate upper wall with a sliding movement along said rearwall during which time said movable Contact moves along said stationarycontact and said opening springpivots said arm to rotate said movablearm to the contacts open position.

9. .In a circuit breaker, a pair of separable contacts, a case enclosingsaidcontacts, a movable contact .arm carrying one of said contactsbetween a contacts closed position and a contacts open position, anopening spring biasing said movable arm to the contacts open position, afirst group of links forming a rst overcenter toggle when said contactsare closed, said first group of links including a handle link tomanually move said movable arm between the contacts open and closedpositions, a second group of links forming a second overcenter toggleindependently stable of said first -overcenter toggle when said contactsare closed, a coupler link pivotally connecting said first group oflinks to said second group of linksand stops limiting overeen-termovement of said toggles, said opening springbiasing overcenter thetoggle formed by said second group of links, a further spring biasingovercenter to the toggle formed by the first group of links, wherebysaid groups of links in the contacts closed position form two togglesindependently stable of the other and of the coupler link.

10. In a circuit breaker, apair of separable contacts, a case enclosingsaid contacts, a movable contact arm carrying one of said contactsbetween a contacts closed position and a contacts open position, anopening spring biasing said movable arm to the contacts open position, afirst group of links forming an overcenter toggle when said contacts areclosed, said first group of links including a handle link to manuallymove said movable arm between the contacts open and closed positions, asecond group of links forming anovercenter toggle when said contacts areclosed, .a coupler link pivotally connecting said first group of linksto said second group of 1inks,.and stops limiting overcenter movement ofsaid toggles, said opening spring biasing overcenter the toggle formedby said second group of links, a further spring biasing overcenter thetoggle formed by the first group of links, whereby said groups of linksin the contacts closed position form two toggles independently stable ofthe other and of the coupler link, said first group of links includingtwo links which with said last mentioned spring jointly form a link ofvariable length. v

11. The structure recited4 in claim 9 wherein said .coupler link islformed of electrical insulation material.

12. In a circuit breaker, a pair of separable contacts, a case enclosingsaid contacts, a movable contact arm carrying one of said contactsbetween a contacts closed position and a contacts open position, anopening spring biasing said movable arm to the contacts open position, afirst group of links forming an overcenter toggle when said contacts areclosed, said first group of links including a handle link to manuallymove said movable arm between the contacts open and closed positions, asecond group of links forming an overcenter toggle when said contactsare closed, a coupler link pivotally connecting said first group oflinks to said second group of links, and stops limiting overcentermovement of said toggles, said ope-ning spring biasing overcenter thetoggle formed by said second group of links, a further spring biasingovercenter the toggle yformed by the first group of links, whereby saidgroups of links in the contacts closed position form two togglesindependently stable of the other and of the coupler link, said secondgroup of links including a catch link, and an electromagnetic means tolatch said catch link to resist the tendency of said second group oflinks t0 collapse under the pressure of the opening spring except onpredetermined electrical currents.

13. In a circuit breaker, a pair of separable contacts, a case enclosingsaid contacts, amovable contact arm carrying one of asid contactsbetween a contacts closed position and a contacts open position, anopening spring biasing said movable arm to the contacts open position, afirst group of links forming an overcenter toggle when said contacts areclosed, said first group of links including a handle link to manuallymove said movable arm between the contacts open and closed positions, asecond group of links forming an overcenter toggle when said contactsare closed, a couplerlink pivotally connecting said first group of linksto said second group of links, and stops limiting overcenter movement ofsaid toggles, said opening spring biasing overcenter the toggle formedby said second group of links, a further spring biasing overcenter thetoggle formed by the first group of links, whereby said groups of linksin the contacts closed positions form two toggles independently stableof the other and of the coupler link, said coupler link being pivotallyconnected to said first and second group of links at locations in whichsaid coupler link is rotatable about its connection to the first groupof links during movement of the second group of links to the cotactsopen position, even though said handle link is manually restrained frommovement.

14. The structure recited in claim 12 and further including a resetspring means disposed in the path of movement of one of the links ofsaid second group subsequent to overload conditions and impingeablethereon when `said first group of links are restrained from movingduring predetermined overload, thereby compressing said reset spring.

15. The structure recited in claim 14 and further including a boosterspring flexed by said reset spring means to further aid in resetting thelinks.

References Cited bythe Examiner UNITED STATES PATENTS y 2,833,886 5/1958Goodwin 200-106 BERNARD A. G1LHEANY,Prr'mary Examiner.

10. IN A CIRCUIT BREAKER, A PAIR OF SEPARABLE CONTACTS, A CASE ENCLOSINGSAID CONTACTS, A MOVABLE CONTACT ARM CARRYING ONE OF SAID CONTACTSBETWEN A CONTACTS CLOSED POSITION AND A CONTACTS OPEN POSITON, ANOPENING SPRING BIASING SAID MOVABLE ARM TO THE CONTACTS OPEN POSITION, AFIRST GROUP OF LINKS FORMING AN OVERCENTER TOGGLE WHEN SAID CONTACTS ARECLOSED, SAID FIRST GROUP OF LINKS INCLUDING A HANDLE LINK TO MANUALLYMOVE SAID MOVABLE ARM BETWEEN THE CONTACTS OPEN AND CLOSED POSITIONS, ASECOND GROUP OF LINKS FORMING AN OVERCENTER TOGGLE WHEN SAID CONTACTSARE CLOSED, A COUPLER LINK PIVOTALLY CONNECTING SAID FIRST GROUP OFLINKS TO SAID SECOND GROUP OF LINKS, AND